Method and System for Adjusting Light Pattern for Structured Light Imaging

ABSTRACT

A system and a method for producing an adjustable light pattern are provided herein. The system may include: a transmitter configured to illuminate a scene with a patterned light being adjusted based on predefined criteria; a receiver configured to receive reflections of the adjusted patterned light; and a computer processor configured to control the adjustment of the patterned light and further analyze the received reflections, to yield a depth map of objects within the scene, wherein the transmitter may include: a light source configured to produce a light beam; a first reflector tiltable approximately along a line on an x-y plane in a Cartesian x-y-z coordinate system; and a second reflector tiltable along a z-axis in said coordinate system, wherein the reflectors are tilted along their respective axes back and forth so as to divert the light beam for creating the adjusted patterned light.

TECHNICAL FIELD

The present invention relates generally to structured light, and moreparticularly, to adjusting light pattern in a structured light system.

BACKGROUND OF THE INVENTION

Prior to setting forth the background of the invention, it may behelpful to set forth definitions of certain terms that will be usedhereinafter.

The term “structured light” as used herein is defined as the process ofprojecting a known pattern of pixels (e.g. grids or horizontal bars) onto a scene. The projected patterned light is deformed when strikingsurfaces and analyzing the deformation allows vision systems tocalculate the depth and surface information of the objects in the scene.For providing further details of how structured light can beimplemented, by way of illustration only, WIPO publication numberWO2013088442 is incorporated herein by reference in its entirety.

The term “spatial coding” as used herein is defined as a fixed patternthat is projected onto the scene and is imaged by the sensor's camera.The fixed pattern is designed in such a way that along epipolar lineseach region of the pattern can be uniquely identify by considering thelocal neighborhood pattern. This method is efficient in terms ofprojected pattern power use and acquisition time, but requiresdedication of several pixels to each label and hence results in lowerspatial resolution. The main disadvantage is that a fixed pattern lacksthe flexibility to respond to different scene conditions by using adifferent pattern. FIG. 1A illustrates a fixed light pattern 100Aexhibiting broken lines according to the prior art. The fixed patternmay be implemented using a mask of phase shifters configured to resultin combination of constructive and destructive interferences.

The term “temporal coding” as used herein is defined as illuminating thescene by a series of patterns. The patterns series are designed in sucha way that each pattern position in a particular epipolar line is codedby a unique time series. The method can be accurate and has flexibility,but is not power efficient and requires a long acquisition time. FIG. 1Billustrates a temporal light pattern 100B according to the prior art,exhibiting a unique vertical line 111, 112, 113, and 114 for each oftime stamps t₁, t₂, t₃, and t₄ respectively.

While the ability to dynamically change the pattern is highly desired,the power inefficiency it ensued makes it very unattractive in manyapplications. In order to allow a dynamic pattern, typically an imagesource is used. Such an image source either scans the sceneprogressively or illuminates it simultaneously, with the image forminglight source modulated to produce the light and dark areas of thepattern. Considering the maximal output of the light source, itsmodulation reduces the “on” time and hence reduces the total outputpower.

Taking, as an example, a constant wave (CW) laser diode as the lightsource projected using a scanning mirror system. Such a laser diode mayemit a certain amount of maximal optical power. When the light ismodulated in order to produce the desired pattern, the average intensityis reduced by the modulation and hence a loss of brightness results.This tradeoff is true for any standard use of image projection method.

SUMMARY OF THE INVENTION

Some embodiments of the present invention overcome the aforementioneddisadvantages of the fixed patterned light, namely lack of flexibility,and the disadvantages of the temporal coding being low energeticefficiency, and a longer acquisition time of the scene.

Embodiments of the present invention provide a system for adjustinglight patterns for structured light imaging devices. The system mayinclude: a transmitter configured to illuminate a scene with a patternedlight being adjusted based on predefined criteria; a receiver configuredto receive reflections of the adjusted patterned light; and a computerprocessor configured to control the adjustment of the patterned lightand further analyze the received reflections, to yield a depth map ofobjects within the scene, wherein the transmitter may include: a lightsource configured to produce a light beam; a first reflector tiltableapproximately along a −45° line on an x-y plane in a Cartesian x-y-zcoordinate system; and a second reflector tiltable along a z-axis insaid coordinate system, wherein the reflectors are tilted along theirrespective axes back and forth so as to divert the light beam forcreating the adjusted patterned light.

These, additional, and/or other aspects and/or advantages of theembodiments of the present invention are set forth in the detaileddescription which follows; possibly inferable from the detaileddescription; and/or learnable by practice of the embodiments of thepresent invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of embodiments of the invention and to showhow the same may be carried into effect, reference will now be made,purely by way of example, to the accompanying drawings in which likenumerals designate corresponding elements or sections throughout.

In the accompanying drawings:

FIGS. 1A and 1B are schematic diagrams illustrating several knownstructured light techniques according to the prior art;

FIG. 2 is a schematic block diagram illustrating a system according toembodiments of the present invention;

FIG. 3 is a schematic diagram illustrating an aspect of the adjustablepattern according to embodiments of the present invention;

FIG. 4 is a schematic diagram illustrating another aspect of theadjustable pattern in accordance with embodiments according to thepresent invention;

FIG. 5 is a schematic diagram illustrating yet another aspect of theadjustable pattern in accordance with embodiments according to thepresent invention;

FIG. 6 is a schematic diagram illustrating yet another aspect of theadjustable pattern in accordance with embodiments according to thepresent invention; and

FIGS. 7A-7C are schematic diagrams illustrating an aspect of the systemin accordance with embodiments according to the present invention.

FIG. 8 is a diagram illustrating an aspect in accordance withembodiments according to the present invention;

FIG. 9 is a high level flowchart illustrating a method in accordancewith embodiments according to the present invention; and

FIG. 10 is a real-life light pattern generated by a system in accordancewith embodiments according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

With specific reference now to the drawings in detail, it is stressedthat the particulars shown are by way of example and for purposes ofillustrative discussion of the preferred embodiments of the presenttechnique only, and are presented in the cause of providing what isbelieved to be the most useful and readily understood description of theprinciples and conceptual aspects of the present technique. In thisregard, no attempt is made to show structural details of the presenttechnique in more detail than is necessary for a fundamentalunderstanding of the present technique, the description taken with thedrawings making apparent to those skilled in the art how the severalforms of the invention may be embodied in practice.

Before explaining at least one embodiment of the present technique indetail, it is to be understood that the invention is not limited in itsapplication to the details of construction and the arrangement of thecomponents set forth in the following description or illustrated in thedrawings. The present technique is applicable to other embodiments or ofbeing practiced or carried out in various ways. Also, it is to beunderstood that the phraseology and terminology employed herein is forthe purpose of description and should not be regarded as limiting.

Unless specifically stated otherwise, as apparent from the followingdiscussions, it is appreciated that throughout the specificationdiscussions utilizing terms such as “processing”, “computing”,“storing”, “determining”, or the like, refer to the action and/orprocesses of a computer or computing system, or similar electroniccomputing device, that manipulate and/or transform data represented asphysical, such as electronic, quantities within the computing system'sregisters and/or memories into other data similarly represented asphysical quantities within the computing system's memories, registers orother such information storage, transmission or display devices.Embodiments of the present invention may include apparatuses forperforming the operations herein. Such apparatuses may be speciallyconstructed for the desired purposes, or may comprise controllers,computers or processors selectively activated or reconfigured by acomputer program stored in the computers. Such computer programs may bestored in a computer readable storage medium (e.g., a non-transitorycomputer readable storage medium), such as, but is not limited to, anytype of disk including floppy disks, optical disks, CD-ROMs,magnetic-optical disks, read-only memories (ROMs), random accessmemories (RAMs) electrically programmable read-only memories (EPROMs),electrically erasable and programmable read only memories (EEPROMs),magnetic or optical cards, or any other type of media suitable forstoring electronic instructions, and capable of being coupled to acomputer system bus. It will be appreciated that a variety ofprogramming languages may be used to implement the teachings of theinvention as described herein.

Embodiments of the invention may include an article such as a computeror processor readable medium, or a computer or processor storage medium,such as for example a memory, a disk drive, or a USB flash memory,encoding, including or storing instructions, e.g., computer-executableinstructions that, when executed by a processor or controller, carry outmethods disclosed herein. Processors may include any standard dataprocessor, such as a microprocessor, multiprocessor, accelerator board,or any other serial or parallel high performance data processor.Embodiments of the invention may be included as part of a computingsystem, such as, for example, a personal computer or workstation whichincludes standard components such as an operating system, a processor, amemory, a disk drive, and input-output devices. Embodiments of thepresent invention may be compatible or integrated with any operatingsystem on any device including, without limitation, the OSX operatingsystem or WINDOWS® operating system. Alternative computer configurationsare possible, and the system and method of the present invention may beimplemented on various suitable computing systems, including, withoutlimitation, hand-held, mountable or mobile computing systems.

FIG. 2 is a schematic block diagram illustrating a system 200 accordingto embodiments of the present invention. System 200 may be implementedby a combination of hardware and software and is configured to generateand analyze an adjustable light pattern wherein the adjustable patternis usable for spatial coding of structured light. System 200 may includea transmitter 210, a receiver 220 and a computer processor 230.

Transmitter 210 (shown in an x-y-z Cartesian coordinate system withX-axis directed to the right, y-axis directed upwards, and z-axisdirected into the page) may include a light source 212 configured togenerate a light beam (e.g., a laser) directed onto a first reflector214 (e.g., a mirror) which is tiltable and controllable (e.g., bycomputer processor 230) so first reflector 214 may tilt around a firstaxis being approximately along the −45° line on the x-y plane in anx-y-z Cartesian coordinate system (e.g., horizontally, denoted H) in aperiodic scanning movement (e.g., scanning back and forth, in asinusoidal motion, a sector of a predefined angle) resulting in foldingthe light beam in a scanning back and forth movement. Similarly,transmitter 210 may further include a second reflector 216 (e.g., amirror) which may be located along the optical path of the light afterit has been folded by the first reflector 214. Second reflector 216 mayalso be both tiltable and controllable (e.g., by computer processor 230)in such a way that second reflector 216 may tilt over a second axisbeing a z-axis in the same x-y-z Cartesian coordinate system (e.g.,vertically, denoted V) in a periodic scanning movement (e.g., scanningback and forth, in a sinusoidal motion, a sector of a predefined angle)wherein the tilt axis of second reflector 216 and the tilt axis of firstreflector 214 are substantially perpendicular (e.g. between +10° and−10° relative to a perpendicular line crossing each of theaforementioned tilt axis). Thus, the light beam reaching secondreflector 216 is folded again (e.g., onto a direction substantiallyparallel to the original direction of the light beam as it left lightsource 212). The synchronized tilting of both reflectors thus create theadjustable light pattern in the scene, whose boundaries can be adjustedand limited for one or more sector within the scene as will be detailedhereinafter.

Furthermore, in accordance with embodiments of the present invention,the scanning speed of first reflector 214 and the scanning speed of thesecond reflector 216 exhibit a constant ratio therebetween (e.g., theratio between the scanning speed of the horizontally scanning reflectorand the scanning speed of the vertically scanning reflector is arational number). In consequence, the patterned light generated bytransmitter 210 and projected onto scene 10 provides a complex harmoniccurve such as a closed Lissajous curve.

According to some embodiments of the present invention the ratio betweenthe two scanning speeds (e.g., horizontal and vertical) is selected togenerate a substantially jigsaw pattern over scene 10 which may becontrolled over time in order to adjust the pattern to various factorswhich may change over time in the scene as will be explained in greaterdetail below.

According to some embodiments of the present invention, first and secondreflectors 214 and 216 may be implemented as mirrors within a microelectro mechanic system (MEMS) having dimensions selected to allow therequired beam distortion. The mirror driving can be electrostatic ormagnetic or Piezoelectric or similar.

According to some embodiments of the present invention light source 212may be a collimated single mode laser with a wavelength of approximately830 nm. The collimation of the light may be achieved by a simple lenseither refractive or diffractive.

Receiver 220 may include optics 222 through which the reflections of thelight pattern from scene 10 are being collected and a sensor 224possibly in the form of a complimentary metal oxide substrate (CMOS)matrix detector. Sensor 224 may be configured to detect the reflectionsin a refresh rate that is sufficient to sense dynamic changes in scene10. Additionally, the rate needs to be adequate to enable observing infull the transmitted pattern which takes time to be drawn along itscurve.

Computer processor 230 may execute computer readable code (e.g., acomputer program or software) that may be configured to control thecomponents of transmitter 210 and further to analyze the reflections ofthe patterned light coming from scene 10 as received and detected byreceiver 220. Specifically, computer processor 230 may be configured toemploy spatial coding techniques known in the art of structured light.To that end, the entire scan generating for example a closed Lissajouscurve is attributed for at least one frame and the integration of sensor224 is selected accordingly. For any given (known) pattern generated bytransmitter 210, computer processor 230 may adjust its analysis tooptimally implement spatial coding as if the pattern was a static one(e.g., transmitted simultaneously to cover a specified sector).

Advantageously, a pattern generated by transmitter 210 as explainedabove enable to tailor a pattern, for structured light imaging systems,based on dynamic characteristics of both the scene and/or the objectswithin it such as a scene, including an object located remotely from thetransmitter (e.g., far field scenario) or alternatively where the objectis located in proximity to the transmitter (e.g., near field scenario).Furthermore, embodiments of the present invention are enabled, whererequired, to use a maximal intensity of light source 212 irrespective ofthe pattern, provided it is a closed Lissajous curve. This may presentan important advantage over scanning-generated light patterns, whichrequire shutting down the light source at various time slots. Thefollowing explains in detail, several exemplary, illustratingnon-limiting embodiments for adjusting the light pattern transmitted bytransmitter 210 and their corresponding advantages and methods of use.

FIG. 3 is a schematic diagram illustrating an aspect of an adjustablepattern according to embodiments of the present invention. Light pattern300 may exhibit a distinctive jigsaw pattern (e.g., a closed Lissajouscurve) where the light line 310 of a constant intensity runs back andforth (possibly at a 200 Hz refresh rate). As explained above, the ratiobetween the vertical scanning speed and the horizontal scanning speed ispreferred to be a rational number so that in each cycle of scanning,pattern 300 remains identical. This is a prerequisite so that a spatialcoding may be achieved. The ratio itself changes over time as will beexplained below, but at all times it is preferred to reflect a rationalnumber. At points where the reflectors (e.g., vertical and horizontal)change the direction of their scanning movements such as at jigsawpoints 312A-312F and also at uppermost and lowermost lines of pattern300, line 310 may be presented as thicker, but in general line 310exhibits approximately constant intensity without unnecessary shutdownsof light source 212. It should be noted that the intensity may somewhatvary along the line due to the speed of the horizontal mirror. In orderto generate a light pattern that is sufficiently dense (e.g., thedistance between the lines at the jigsaw pattern relative to the coveredarea), a ratio between a horizontal axis and a vertical axis ofapproximately 1:10 and higher may be required. It should be noted thatthe aforementioned ratio dictates the number of lines, so 1:10 will giveonly 10 lines and usually more lines are required for practicalapplication (e.g., 100 or more lines). The higher scanning speed isrequired along a stereoscopic axis (being the axis along which astereoscopic image is created from two viewpoints), which is often thevertical axis in structured light applications using lines patternedlight in which the objects to be tracked are vertically oriented, suchas the head or the palm of the hand of a user. It is noted that thedepth map that is extracted from the reflections of the pattern may beused for recognition of postures and gestures made by the hand of theuser or any other body part in accordance with certain embodiments ofthe present application.

FIG. 4 is a schematic diagram illustrating another aspect of theadjustable pattern in accordance with embodiments according to thepresent invention. Light pattern 400 illustrates dimensional adjustmentin which the light pattern is concentrated at a region of interest 420(ROI) being a subset of area 410 defining a potential coverage of thepattern 400 by the transmitter. The dimension adjustment of pattern 400may be achieved by adjusting the span of the scan of each of the one ormore reflectors so that they each cover a smaller sector. Limiting thescanning span of the reflectors may affect the ratio between verticaland horizontal scanning and therefore attention should be drawn tomeeting the closed Lissajous curve requirements. Illuminating a ROI 420may be useful for improving signal to noise ratio (SNR) and signal tobackground ratio by putting more light onto the desired region ofinterest. ROI illumination may also be useful whenever a specificobject, such as a palm of a hand 430, requires higher illuminationintensity or when other objects in the scene should not be illuminatedat all.

FIG. 5 is a schematic diagram illustrating yet another aspect of anadjustable pattern in accordance with certain embodiments of the presentinvention. Light pattern 509 illustrates adjusting an original (maximal)area 510 into two (or more) ROIs—region 520 (directed at the palm of thehand) and region 530 directed at the head of the user. As opposed to theadjustment illustrated in FIG. 4 above, the dimensional adjustment hereis carried out by shutting down the illumination beam at any pixel otherthan ROIs 520 and 530. This leads to some energetic inefficiencycompared with the adjustment pattern illustrated in FIG. 4. However, theuse of multiple ROIs may sometimes be needed according to the type ofstructured light application such as when simultaneous illumination ofdifferent objects at a single scan cycle.

Similarly, instead of shutting down the illumination source itsintensity can be adjusted in order to overcome strong variations in thescene reflectivity. In such a way more reflective scene parts will beprojected with lower intensity pattern in order to avoid saturation andincrease the sensing dynamic range.

FIG. 6 is a schematic diagram illustrating yet another aspect of theadjustable pattern in accordance with embodiments according to thepresent invention. Light patterns 610, 620 and 630 are similar exceptfor a different vertical displacement from a common base line. Inaccordance with some embodiments, it would be possible to adjust thelight pattern over time and present a different pattern for each frame(possibly periodically). Here, for instance, each of light patterns 610,620 and 630 correspond with a series of Frame A, Frame B, and Frame Cand so forth. The adjustment over time may be advantageous for obtaininga higher resolution from the multiple exposures. An example for that isshifting the pattern up by a fraction of the distance between lines,hence getting larger vertical lines resolution. Implementing multipleexposures requires a slow varying scene in order to be able to achievemultiple exposures. As in all other adjustments to the pattern generatedby the transmitter, the receiver is provided with data relating to theadjustment applied to the pattern so the analysis, per adjusted pattern,still resembles a spatial coding as known in the art.

FIGS. 7A-7C are schematic diagrams illustrating an aspect of the systemin accordance with certain embodiments of the present invention. FIG. 7Bdepicts a top view of a room 730B with a system 200 in accordance withembodiments of the present invention located near one of the walls. Asillustrated, patterned light is transmitted from system 200 and some ofit, particularly the light coming from the right side and the left sideof system 200, hits walls 740B of room 730B. Due to the aforementionedgeometry of room 730B it would be beneficial if the light pattern used,as shown in FIG. 7A and marked 700, exhibits variable intensity levelwith lower intensity lines 720A at the regions right of line 710B andleft of line 710A. In other embodiments, the decrease in line intensitymay be gradual and tailored per the geometry of the room. FIG. 7Cillustrates an oval shaped room 730C with walls 740C in which a totallydifferent pattern may be needed (possibly with more uniform intensityfor the pattern line). Embodiments of the present invention willdetermined the geometry of the room and adjust the light patternaccordingly in order to improve the effectiveness of the structuredlight system.

FIG. 8 illustrates yet another aspect of the present invention. Pattern800 exhibits one or more notches 820 (it should be noted that not allnotches are indicated) along its line 810 wherein, for each horizontalline, the notches are positioned at a different location. This featuremay serve for indexing the lines by enabling distinguishing between thespecific lines at the receiver, based on the location of the notch. Thenotch may be any omission of light along a specified segment.

FIG. 9 is a high level flowchart illustrating a method in accordancewith certain embodiments of the present invention. Method 900 includesobtaining pattern adjustment parameters 910. These can be user definedor automatically defined, and are tailored based on the application. Thescene may then be illuminated with the adjusted pattern 920 and thereflections of the adjusted pattern are detected 930 where, in certainembodiments, the detection of the entire adjusted pattern is carried outin a single exposure per pattern. Additional exposures are contemplated.Finally, the reflections are analyzed for generating a depth map 940 ina way similar to other structured light methods.

FIG. 10 is a real-life light pattern generated by a system in accordancewith certain embodiments of the present invention. As can be seen inpattern 1000 a back and forth sinusoidal motion at a ratio ofapproximately 1:100 with the horizontal scan generates an approximationof a line pattern.

Advantageously, embodiments of the present invention serve as anefficient bridge between spatial and temporal structured lighttechniques. Embodiments present a momentarily fixed pattern which allowsfast extraction of 3D data, but it can also modify the pattern todynamically adapt it to changing scene conditions and requirements. Thedynamic change can be devised to gradually enhance the information onthe current scene or to optimize the data acquisition in terms of power,signal to noise ratio, and coping with background.

Advantageously, embodiments of the present invention present anefficient way to produce a pattern allowing utilization of the availablelight source to its maximal potential without requiring ineffective“off” time unnecessarily.

Thus, methods according to certain embodiments of the present inventionovercome the main drawback of temporal structure light techniques byusing a pattern that is fully light “on” based, and overcome the maindrawback of spatial structured light techniques, which is the rigidityof the pattern that cannot be adapted to varying conditions.

In the above description, an embodiment is an example or implementationof the inventions. The various appearances of “one embodiment,” “anembodiment”, “certain embodiments” or “some embodiments” do notnecessarily all refer to the same embodiments.

Although various features of the invention may be described in thecontext of a single embodiment, the features may also be providedseparately or in any suitable combination. Conversely, although theinvention may be described herein in the context of separate embodimentsfor clarity, the invention may also be implemented in a singleembodiment.

Reference in the specification to “some embodiments”, “an embodiment”,“one embodiment”, “certain embodiments” or “other embodiments” meansthat a particular feature, structure, or characteristic described inconnection with the embodiments is included in at least someembodiments, but not necessarily all embodiments, of the inventions.

It is to be understood that the phraseology and terminology employedherein is not to be construed as limiting and are for descriptivepurposes only.

The principles and uses of the teachings of the present invention may bebetter understood with reference to the accompanying description,figures and examples.

It is to be understood that the details set forth herein do not construea limitation to an application of the invention.

Furthermore, it is to be understood that the invention can be carriedout or practiced in various ways and that the invention can beimplemented in embodiments other than the ones outlined in thedescription above.

It is to be understood that the terms “including”, “comprising”,“consisting” and grammatical variants thereof do not preclude theaddition of one or more components, features, steps, or integers orgroups thereof and that the terms are to be construed as specifyingcomponents, features, steps or integers.

If the specification or claims refer to “an additional” element, thatdoes not preclude there being more than one of the additional element.

It is to be understood that where the claims or specification refer to“a” or “an” element, such reference is not be construed that there isonly one of that element.

It is to be understood that where the specification states that acomponent, feature, structure, or characteristic “may”, “might”, “can”or “could” be included, that particular component, feature, structure,or characteristic is not required to be included.

Where applicable, although state diagrams, flow diagrams or both may beused to describe embodiments, the invention should not be considered aslimited to those diagrams or to the corresponding descriptions. Forexample, flow need not move through each illustrated box or state, or inexactly the same order as illustrated and described.

Methods of the present invention may be implemented by performing orcompleting manually, automatically, or a combination thereof, selectedsteps or tasks.

The descriptions, examples, methods and materials presented in theclaims and the specification are not to be construed as limiting butrather as illustrative only.

Meanings of technical and scientific terms used herein are to becommonly understood as by one of ordinary skill in the art to which theinvention belongs, unless otherwise defined.

The present invention may be implemented in the testing or practice withmethods and materials equivalent or similar to those described herein.

While the invention has been described with respect to a limited numberof embodiments, these should not be construed as limitations on thescope of the invention, but rather as exemplifications of some of thepreferred embodiments. Other possible variations, modifications, andapplications are also within the scope of the invention. Accordingly,the scope of the invention should not be limited by what has thus farbeen described, but by the appended claims and their legal equivalents.

1. A system comprising: a transmitter configured to illuminate a scenewith a patterned light being adjusted based on predefined criteria; areceiver configured to receive reflections of the adjusted patternedlight; and a computer processor configured to control the adjustment ofthe patterned light and further analyze the received reflections, toyield a depth map of objects within the scene, wherein the transmittercomprises: a light source configured to produce a light beam; a firstreflector tiltable on an x-y plane in a Cartesian x-y-z coordinatesystem; and a second reflector tiltable along a z-axis in said Cartesianx-y-z coordinate system, wherein the reflectors are tilted along theirrespective axes so as to divert the light beam for creating the adjustedpatterned light.
 2. The system according to claim 1, wherein theanalysis of the received reflections is based on spatial coding of thepatterned light.
 3. The system according to claim 1, wherein thepatterned light is a closed Lissajous curve.
 4. The system according toclaim 1, wherein the adjustment of the pattern is carried out bylimiting the scan of the reflectors to a limited sector within thespecified sector.
 5. (canceled)
 6. The system according to claim 1,wherein the adjustment of the pattern is carried out by reducing theintensity of the light beam to create regions of interest (ROIs) inwhich the patterned light is illuminating.
 7. The system according toclaim 1, wherein the adjustment comprise setting a different patternedlight for each frame of scene captured by a sensor.
 8. The systemaccording to claim 1, wherein the adjustment comprises setting adifferent intensity for different segments of the patterned light. 9-10.(canceled)
 11. The system according to claim 1, wherein the computerprocessor is further configured to control a relative frequency tochange number of lines in the pattern.
 12. The system according to claim1, wherein the computer processor is further configured to generatemultiple exposures to yield a higher resolution.
 13. The systemaccording to claim 1, wherein the first reflector is tiltableapproximately along a 45° line on the x-y plane.
 14. The systemaccording to claim 1, wherein the reflectors are tiltable back and forthalong their respective axes.
 15. A method of illuminating a scene with apatterned light being adjusted based on predefined criteria, the methodcomprising: producing a light beam; tilting a first reflector on an x-yplane in a Cartesian x-y-z coordinate system; tilting a second reflectoralong a z-axis in said Cartesian x-y-z coordinate system, wherein thetilting of both reflectors is coordinated so as to divert the light beamfor creating the adjusted patterned light; receiving reflections of theadjusted patterned light; controlling the adjustment of the patternlight; and analyzing the received reflections to yield a depth map ofobjects within the scene.
 16. The method according to claim 15, whereinthe analysis of the received reflections is based on spatial coding ofthe patterned light.
 17. The method according to claim 15, wherein thepatterned light is a close Lissajous curve.
 18. (canceled)
 19. Themethod according to claim 15, wherein the adjustment of the pattern iscarried out by reducing the intensity of the light beam to createregions of interest (ROIs) in which the patterned light is illuminating.20. The method according to claim 15, wherein the adjustment comprisesetting a different patterned light for each frame of scene captured bya sensor.
 21. The method according to claim 15, wherein the adjustmentcomprises setting a different intensity for different segments of thepatterned light. 22-23. (canceled)
 24. The method according to claim 15,wherein the tilting of the first reflector is approximately along a 45°line on the x-y plane.
 25. The method according to claim 15, wherein thetilting of the reflectors is carried out back and forth along theirrespective axes.
 26. A system comprising: a transmitter configured toilluminate a scene with a patterned light being adjusted based onpredefined criteria; a receiver configured to receive reflections of theadjusted patterned light; and a computer processor configured to controlthe adjustment of the pattern light and further analyze the receivedreflections, to yield a depth map of objects within the scene, whereinthe transmitter comprises at least two controllable reflectorssynchronized to generate a closed Lissajous curve as the adjustedpatterned light.